It has been a problem in the art of vacuum lift systems to provide complete flexibility in the handling and positioning of loads. Some loads such as burlap bags cannot efficiently be grasped by the vacuum lift head directly and thus auxiliary clamping accessories are desirable. Other types of loads such as rolls may require rotation about their axis in moving from a horizontal position on a pallet to a vertical position on a spindle, and thus an auxiliary powered rotating mechanism is desirable. However, heretofore the supply of power to the auxiliary accessories has created safety and ergonomic problems, because electric line cords or pneumatic lines tend to snag, trip operating personnel or become twisted, coiled and untidy in the course of use.
A further problem is incurred in handling of loads with vacuum lift systems in that complete flexibility of movement of the load is restricted by the necessity to convey the vacuum energy through sealed conveyance paths that do not readily accommodate movable joints. Thus, if a rotatable joint is considered desirable for better manipulation of the lift head and accompanying load, the necessity of providing a conventional vacuum sealed joint introduces short wear life and significant friction that defeats the purpose of reducing manual work to a minimum. Also rotary joints do not easily accommodate the conveyance of two diverse sources of power to the lift head, particularly if one source of power is a pneumatic tube for carrying compressed air. Limitation of rotary joints to less than 360 degree rotation for accommodating auxiliary power lines, so that they do not become entangled sacrifices the freedom to position loads universally in any degree of motion.
It is accordingly an object of this invention to provide an auxiliary source of power at the lift head for with accessories that is safe, neat and convenient to use.
It is a further object of this invention to provide an improved rotary joint that requires little manual effort and permits 360 degree rotation.